LEP and malnutrition: Leptin is a 16-kDa protein hormone and a product of obesity gene (ob) which is produced exclusively by adipocytes and its main effect on hypothalamus that decreases appetite, increases energy expenditure, and reduces weight.4, 5 According to the studies, it seems that increase of serum leptin in patients on chronic hemodialysis may cause anorexia and malnutrition.6